So I have a lot of questions and I hope that someone will be able to help me. I am wondering if it would be worth it to start mining now. I have never mined before and when I want to buy bitcoins I always have to do it a sketchy way. I am wondering what setup I should get. I have it to be about 3 Ghash/s (maybe more?) if possible.

I have looked it up before and it seems that people that are currently bitcoin mineing are steering away noobs from trying it. I am just wondering why? I know they mention electricity bills a lot like if you would even be profiting from mining after you pay the electric bill. But my solution was setting it up at my school. I am in computer networking and if I decide to do this my teacher would probably let me set it up in the back room or something. Now would this be a good idea or something I should not even consider.

Also once I am done using bitcoins I need and I want to sell them where am I supposed to do so? I know on ebay you can but its against there policy and there are a lot of scammers. I also hate Paypal so I would never accept Paypal as payment first off becaus I don't use it and second there are to many scammers. So I am just wondering what your guys opinion on this is and what should I do.